A13: Price-Tracking Worksheet

DeFi Builder: Deploy Your Own DEX

Group Members:

Date:

1. Contract Addresses

Record the addresses of your deployed contracts:

Token A Name:

Token A Address:

Token B Name:

Token B Address:

DEX Address:

2. Initial Liquidity

Record the amounts you added as initial liquidity:

Field	Value
Amount of Token A added
Amount of Token B added
Initial Reserve A (from DEX)
Initial Reserve B (from DEX)
Initial k = Reserve A x Reserve B

Swap Output Formula: amountOut = (reserveOut x amountIn) / (reserveIn + amountIn)

3. Swap Results

Fill in each row after executing the corresponding swap. Use the post-previous-swap reserves for each new calculation.

Swap	Direction	Amount In	Amount Out	Effective Price	Price Impact
Initial	-	-	-	1.0000	-
Swap 1 (small)	A → B
Swap 2 (medium)	A → B
Swap 3 (large)	A → B
Swap 4 (reverse)	B → A

How to calculate each column:
Effective Price: Amount Out / Amount In (for A→B swaps, this is "B per A")
Price Impact: (1.0 - Effective Price) x 100% for A→B swaps (how much worse than the initial 1:1 rate)
k verification: Multiply Reserve A x Reserve B. It should be approximately the same as your initial k.

4. Analysis Questions

Q1: Why does a larger swap give a worse effective price? Explain using your data. (1.5 pts)

Q2: Does x x y = k hold exactly after each swap? If not, why? (1 pt)

Q3: What happened when you swapped in the reverse direction (B → A)? Why was the rate different from 1:1? (1.5 pts)

5. Summary Observations

In 2-3 sentences, describe the most important thing you learned from this experiment:

6. Bonus Extensions (Optional, +10 pts)

If you attempted a bonus challenge, describe what you did below.

Bonus A: Slippage Protection (+5 pts)

Did you add a _minOut parameter to the swap function?

Bonus B: Simple Escrow (+5 pts)

Did you deploy and demonstrate the Escrow contract?